When a universal mobile telecommunications system (UMTS) technology evolves to Release Rel-11, a multiflow transmission (Multiflow) feature is introduced. This feature allows a plurality of intra-frequency or inter-frequency cells to be configured as high-speed downlink shared channel (HS-DSCH) serving cells of a user equipment (UE), which obviously improves user experience. In UMTS Rel-7, a downlink discontinuous reception (DRX) feature is introduced, which can allow a UE to receive downlink data in a discontinuous manner, thereby reducing power consumption of the UE. In a case of the Multiflow, there may be certain timing differences between downlink common channels of a plurality of intra-frequency HS-DSCH serving cells, which are mainly caused by base station clock timing corresponding to the cells, timing offsets (Tcell) of the cells, and timing differences (Tp) introduced by air interface transmission.
A timing relationship between HS-DSCH serving cells may specifically include a high speed shared control channel (HS-SCCH), a high speed physical downlink shared channel (HS-PDSCH), a high speed dedicated physical control channel (HS-DPCCH), and a fractional dedicated physical channel (F-DPCH), where the HS-PDSCH is a channel for indicating HSDPA data transmission; the HS-SCCH carries data indication information, for example, an identifier for scheduling a UE; the HS-PDSCH carries specific data information; the HS-DPCCH carries feedback indication information for downlink data, for example, a channel condition indication and data reception feedback indication information; and the F-DPCH channel is a dedicated channel, and is used for performing power control on a dedicated channel and performing control on data transmit power of an uplink channel of a UE. These channels have fixed timing relationships. Seen from the perspective of a cell side, it is necessary to find a start point of the HS-DPCCH to receive uplink data; according to protocol specifications, a cell needs to find backwards, according to an HS-SCCH start point, an HS-DPCCH boundary that is closest to 1280 chips as a boundary.
Using a single frequency dual cell (SF-DC) feature as an example, in a case of the SF-DC feature, there are two serving cells. There is a certain timing difference of cells between downlink common channels within the cells, and the two cells may belong to a same base station or different base stations. In the case of the SF-DC, a UE needs to receive data in two cells in the downlink direction, but only needs to perform sending in one cell, and the other cell also needs to demodulate data (in an inter-base station SF-DC scenario). This requires a UE side to specify a matching relationship between subframes for receiving downlink data. The two cells of the UE may be separately defined as a time reference cell and a non-time reference cell, where timing of channels between the time reference cell and the UE is same as channel timing specified in Rel-5 HSDPA, and the other cell is the non-time reference cell. For example, HS-SCCH S_DRX=0 in the time reference cell of the UE is matched with HS-SCCH S_DRX=0 in the non-time reference cell; then, after the UE receives data of the two subframes, the UE performs, in the time reference cell, feedback on the HS-DPCCH according to an existing timing rule, where there is a fixed timing relationship between the HS-DPCCH and the HS-SCCH. For the non-time reference cell, a boundary of the HS-DPCCH is also searched for according to a protocol. However, because of the timing difference between the downlink common channels of the cells, an error may occur when the UE or the non-time reference cell searches for the boundary of the HS-DPCCH. Because the UE side receives HS-SCCH S_DRX=0 of the two cells at the same time and performs feedback through one HS-DPCCH, the UE or the non-time reference cell may incorrectly locate an HS-DPCCH boundary, which eventually affects downlink data transmission performance.